Quality Assurance of Test Method Performance

2008 ◽  
pp. 188-188-5
Author(s):  
SJ Rand ◽  
ATC Lau
Keyword(s):  
Quality Assurance ◽  
Test Method ◽  
Method Performance

scholarly journals Adaptation of the Systematic Review Framework to the Assessment of Toxicological Test Methods: Challenges and Lessons Learned With the Zebrafish Embryotoxicity Test

2019 ◽  
Vol 171 (1) ◽  
pp. 56-68
Author(s):  
Martin L Stephens ◽  
Sevcan Gül Akgün-Ölmez ◽  
Sebastian Hoffmann ◽  
Rob de Vries ◽  
Burkhard Flick ◽  
...  
Keyword(s):  
Systematic Review ◽  
Developmental Toxicity ◽  
Test Methods ◽  
Lessons Learned ◽  
Hazard Identification ◽  
Test Method ◽  
Main Study ◽  
Systematic Review Methodology ◽  
Method Performance ◽  
Toxicological Test

AbstractSystematic review methodology is a means of addressing specific questions through structured, consistent, and transparent examinations of the relevant scientific evidence. This methodology has been used to advantage in clinical medicine, and is being adapted for use in other disciplines. Although some applications to toxicology have been explored, especially for hazard identification, the present preparatory study is, to our knowledge, the first attempt to adapt it to the assessment of toxicological test methods. As our test case, we chose the zebrafish embryotoxicity test (ZET) for developmental toxicity and its mammalian counterpart, the standard mammalian prenatal development toxicity study, focusing the review on how well the ZET predicts the presence or absence of chemical-induced prenatal developmental toxicity observed in mammalian studies. An interdisciplinary team prepared a systematic review protocol and adjusted it throughout this piloting phase, where needed. The final protocol was registered and will guide the main study (systematic review), which will execute the protocol to comprehensively answer the review question. The goal of this preparatory study was to translate systematic review methodology to the assessment of toxicological test method performance. Consequently, it focused on the methodological issues encountered, whereas the main study will report substantive findings. These relate to numerous systematic review steps, but primarily to searching and selecting the evidence. Applying the lessons learned to these challenges can improve not only our main study, but may also be helpful to others seeking to use systematic review methodology to compare toxicological test methods. We conclude with a series of recommendations that, if adopted, would help improve the quality of the published literature, and make conducting systematic reviews of toxicological studies faster and easier over time.

scholarly journals Single-Laboratory Validation Study of a Proton NMR Method for the Determination of L-Arginine, L-Citrulline, and Taurine Contents in Dietary Supplements

2020 ◽  
Vol 103 (4) ◽  
pp. 1140-1147
Author(s):  
Isaac Lee ◽  
Jennie Vo ◽  
Quanyin Gao ◽  
Piyush Purohit ◽  
Veronica Zarraga ◽  
...  
Keyword(s):  
Quality Control ◽  
Dietary Supplement ◽  
Proton Nmr ◽  
Hplc Method ◽  
Rapid Analysis ◽  
Test Method ◽  
Method Performance ◽  
Single Laboratory ◽  
Concentration Levels

Abstract Background A quantitative NMR (qNMR) method can provide rapid analysis compared to chromatographic methods. Sample preparation steps are relatively simpler and run time is shorter. Rapid analysis methods for release tests in quality control laboratories are very important for laboratory efficiency. Here, we describe a single-laboratory validation study for a rapid qNMR analysis of L-arginine, L-citrulline, and taurine in powdered and tablet dietary supplement products. Objectives This validation work is to provide documented evidence for the qNMR method validity as well as method performance. Methods The method used Bruker 400 MHz high-resolution proton NMR spectroscopy for simultaneous determination of L-arginine, L-citrulline, and taurine contents in dietary supplement product 1 (powder) and dietary supplement product 2 (tablet). The absolute NMR quantitation is based on a principle of universal proton response intensity correlation with the number of protons in each target analyte (amino acids) vs. that of a reference standard (maleic acid). Results The test method performance was validated with dietary supplement-1 (powder) and dietary supplement-2 (tablet). The linearity of the method was studied from about 360 mg/g to about 675 mg/g of L-arginine; from about 15 mg/g to about 30 mg/g of L-citrulline; and from about 20 mg/g to about 40 mg/g of taurine in dietary supplement-1, and from about 15 mg/g to about 30 mg/g of taurine in dietary supplement-2. The coefficients of determination (R2) are 1.0000 for L-arginine, 0.9967 for L-citrulline, and 0.9995 for taurine in dietary supplement-1 and 0.9903 for taurine in dietary supplement-2. The accuracies measured from the sample matrices are 102%, 101%, and 100% average recoveries for 80%, 100%, and 120% concentration levels of L-arginine, 105%, 105%, and 103% average recoveries for 80%, 100%, and 120% concentration level of L-citrulline, and 101%, 102%, and 100% average recoveries of taurine for 80%, 100%, 120% concentration levels in dietary supplement-1; and 95, 98%, and 93% average recoveries of taurine for 80%, 100%, 120% concentration levels in dietary supplement-2, respectively. The precisions (RSD) are 1% for L-arginine, 5% for L-citrulline, and 2% for taurine in dietary supplement -1, respectively; and 4% for taurine in dietary supplement-2. The ruggedness of the test method is within 2%, 4%, and 2% for L-arginine, L-citrulline, and taurine for dietary supplement -1, respectively, and within 4% for dietary supplement-2. The method is specific for the quantitation of each nutrient with no background interference from the matrix for the proton peaks of L-arginine, L-citrulline, taurine, and maleic acid (standard). Conclusions The test method is proven to be specific, precise, accurate, rugged, and suitable for intended quantitative analysis of L-arginine, L-citrulline, and taurine in powdered and tablet finished products. Highlights The simultaneous determination of all three nutrients of L-arginine, L-citrulline, and taurine using proton NMR provides rapid analysis for quality control release tests that is more efficient versus that of two HPLC methods. Previously, our laboratory was using one HPLC method to analyze L-arginine and L-citrulline while using a second HPLC method to analyze taurine. That approach required two HPLC instruments and two analysts for parallel analysis that takes 2 days using volatile and flammable solvents for extraction and chemical derivatization. This rapid NMR method can analyze the sample “as is” with results obtained in less than 4 h, and is efficient, safe, and environmentally friendly. The initial higher NMR instrument investment versus two HPLC instruments is rewarded with high returns for continued quality control tests.

scholarly journals Lung and Intercostal Upper Abdomen Ultrasonography for Staging Patients with Ovarian Cancer: A Method Description and Feasibility Study

Diagnostics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 85
Author(s):  
Maciej Stukan ◽  
Antonio Bugalho ◽  
Amanika Kumar ◽  
Julita Kowalewska ◽  
Dariusz Świetlik ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Ultrasound Examination ◽  
Test Method ◽  
Pathological Examination ◽  
Lung Ultrasonography ◽  
Reference Standard ◽  
Method Performance ◽  
Tumor Spread ◽  
The Right ◽  
Upper Abdomen

A detailed transabdominal and transvaginal ultrasound examination, performed by an expert examiner, could render a similar diagnostic performance to computed tomography for assessing pelvic/abdominal tumor spread disease in women with epithelial ovarian cancer (EOC). This study aimed to describe and assess the feasibility of lung and intercostal upper abdomen ultrasonography as pretreatment imaging of EOC metastases of supradiaphragmatic and subdiaphragmatic areas. A preoperative ultrasound examination of consecutive patients suspected of having EOC was prospectively performed using transvaginal, transabdominal, and intercostal lung and upper abdomen ultrasonography. A surgical-pathological examination was the reference standard to ultrasonography. Among 77 patients with histologically proven EOC, supradiaphragmatic disease was detected in 13 cases: pleural effusions on the right (n = 12) and left (n = 8) sides, nodular lesions on diaphragmatic pleura (n = 9), focal lesion in lung parenchyma (n = 1), and enlarged cardiophrenic lymph nodes (n = 1). Performance (described with area under the curve) of combined transabdominal and intercostal upper abdomen ultrasonography for subdiaphragmatic areas (n = 77) included the right and left diaphragm peritoneum (0.754 and 0.575 respectively), spleen hilum (0.924), hepatic hilum (0.701), and liver and spleen parenchyma (0.993 and 1.0 respectively). It was not possible to evaluate the performance of lung ultrasonography for supradiaphragmatic disease because only some patients had this region surgically explored. Preoperative lung and intercostal upper abdomen ultrasonography performed in patients with EOC can add valuable information for supradiaphragmatic and subdiaphragmatic regions. A reliable reference standard to test method performance is an area of future research. A multidisciplinary approach to ovarian cancer utilizing lung ultrasonography may assist in clinical decision-making.

scholarly journals Performance Evaluation of Direct Forced-Air Total Solids and Kjeldahl Total Nitrogen Methods: 1990 through 1995

1997 ◽  
Vol 80 (5) ◽  
pp. 1038-1043 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
Patrick A Healy ◽  
J Richard Fleming
Keyword(s):  
Quality Assurance ◽  
Total Nitrogen ◽  
Collaborative Study ◽  
Quality Assurance Program ◽  
Drying Method ◽  
Method Performance ◽  
Collaborative Studies ◽  
Aoac Method ◽  
Forced Air

Abstract Results from collaborative studies of the performance of the direct forced-air oven-drying method for determination of milk total solids content (AOAC Method 990.20) and the Kjeldahl total nitrogen method for determination of milk total nitrogen content (AOAC Method 991.20) were published in 1989 and 1990, respectively. Method performance was characterized by using the harmonized ISC7IUPAC/ AOAC guidelines for method validation, and the methods now have final action status. During1990 through 1995, the split sample collaborative study format was used to monitor the performance of these methods as part of a multilaboratory quality assurance program. Seven blind duplicate milk materials were sent from a central laboratory onceevery 2 months to participating laboratories. Data were analyzed with the same statistical procedures used in the original collaborative studies. Compared with the original collaborative study, the repeatability and reproducibility of the oven-drying method improved over time. For the Kjeldahl total nitrogen method, within-laboratory repeatability improved slightly, whereas between-laboratory reproducibility was similar to but not always as good as in the original study. The results demonstrate that the statistical protocol for collaborative studies can be used effectively as the basis for a multilaboratory quality assurance program and that the method performance achieved in a collaborative study can be maintained and even improved with time.

REPRODUCIBILITY OF RADON-IN-WATER MEASUREMENTS BY EMANOMETRY TECHNIQUE

2020 ◽  
Vol 191 (2) ◽  
pp. 166-170
Author(s):  
C Di Carlo ◽  
G Venoso ◽  
L Lepore ◽  
M Ampollini ◽  
C Carpentieri ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Detection Limit ◽  
Water Samples ◽  
Test Method ◽  
Measuring System ◽  
Measuring Systems ◽  
Detection Techniques ◽  
Transport Container ◽  
Sample Transfer ◽  
Radon In Water

Abstract The emanometry test method is one of the detection techniques of radon in water satisfying requirements of Directive 2013/51/Euratom with regards to the detection limit. Quality assurance (QA) procedures were developed and implemented for a measuring system relying on such a technique. These procedures mainly address the following: (i) the assembling of each component of the degassing circuit, (ii) the sample transfer from the transport container to the degassing vessel and (iii) the control of all the influencing quantities. Three identical measuring systems have been used to analyse in parallel 39 water samples with the aim to evaluate the effectiveness of QA procedures in terms of reproducibility. The results showed quite low variability (<15% for the 84% of measurements in the range 10–100 Bq L−1) among the three different measuring systems.

An investigation of new toxicity test method performance in validation studies: 2. comparison of three measures of toxicity test performance

2002 ◽  
Vol 21 (6) ◽  
pp. 313-323 ◽  
Author(s):  
L H Bruner ◽  
G J Carr ◽  
J W Harbell ◽  
R D Curren
Keyword(s):  
Test Performance ◽  
Predictive Value ◽  
Validation Studies ◽  
Toxicity Test ◽  
Prediction Interval ◽  
Test Method ◽  
Data Sets ◽  
Method Performance ◽  
Quantitative Measurements ◽  
Sensitivity Specificity

An area that requires further research is how best to measure test method performance in validation studies and how to set criteria that should be used to judge the adequacy of this performance. The studies reported here were designed to begin an investigation of these questions. Computer simulations were used to generate data sets similar to those that might be obtained from a large validation study. These data were then analysed using three procedures including determination of the 95% prediction interval (PI), calculation of Pearson's correlation coefficient and calculation of the contingent probability statistics (CPS), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The results of this work suggest that of the three approaches examined, quantitative measurements with calculation of the 95% PI provide the most information to allow discrimination between the performance of several different NTMs. The results also suggest that dividing data sets into positive and negative toxicity classifications followed by the calculation of CPS leads to considerable information loss. This loss of information may be so significant that it is not possible in certain circumstances to distinguish between NTMs that are adequate and those that are not.

An investigation of new toxicity test method performance in validation studies: 1. toxicity test methods that have predictive capacity no greater than chance

2002 ◽  
Vol 21 (6) ◽  
pp. 305-312 ◽  
Author(s):  
L H Bruner ◽  
G J Carr ◽  
J W Harbell ◽  
R D Curren
Keyword(s):  
Predictive Value ◽  
Validation Studies ◽  
Toxicity Test ◽  
High Sensitivity ◽  
Test Methods ◽  
Test Method ◽  
Predictive Capacity ◽  
Worst Case ◽  
Method Performance ◽  
Sensitivity Specificity

An approach commonly used to measure new toxicity test method (NTM) performance in validation studies is to divide toxicity results into positive and negative classifications, and then identify true positive (TP), true negative (TN), false positive (FP) and false negative (FN) results. After this step is completed, the contingent probability statistics (CPS), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) are calculated. Although these statistics are widely used and often the only statistics used to assess the performance of toxicity test methods, there is little specific guidance in the validation literature on what values for these statistics indicate adequate performance. The purpose of this study was to begin developing data-based answers to this question by characterizing the CPS obtained from an NTM whose data have a completely random association with a reference test method (RTM). Determining the CPS of this worst-case scenario is useful because it provides a lower baseline from which the performance of an NTM can be judged in future validation studies. It also provides an indication of relationships in the CPS that help identify random or near-random relationships in the data. The results from this study of randomly associated tests show that the values obtained for the statistics vary significantly depending on the cut-offs chosen, that high values can be obtained for individual statistics, and that the different measures cannot be considered independently when evaluating the performance of an NTM. When the association between results of an NTM and RTM is random the sum of the complementary pairs of statistics (sensitivity+ specificity, NPV+PPV) is approximately 1, and the prevalence (i.e., the proportion of toxic chemicals in the population of chemicals) and PPV are equal. Given that combinations of high sensitivity–low specificity or low specificity–high sensitivity (i.e., the sum of the sensitivity and specificity equal to approximately 1) indicate lack of predictive capacity, an NTM having these performance characteristics should be considered no better for predicting toxicity than by chance alone.

Performance Evaluation of the Babcock and Ether Extraction Methods: 1989 through 1992

1994 ◽  
Vol 77 (4) ◽  
pp. 976-981 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
Patrick A Healy ◽  
J Richard Fleming
Keyword(s):  
Quality Assurance ◽  
Collaborative Study ◽  
Raw Milk ◽  
Extraction Methods ◽  
Quality Assurance Program ◽  
Method Performance ◽  
Collaborative Studies ◽  
Ether Extraction ◽  
Ongoing Quality Assurance

Abstract Results of the collaborative studies of the performance of the Babcock method (989.04) and the modified Mojonnier ether extraction method (989.05) for the determination of the fat content of raw milk were published in 1988. Method performances were characterized by using the harmonized International Organization for Standardization–International Union of Pure and Applied Chemistry–Association of Official Analytical Chemists (ISO/IUPAC/AOAC) guidelines for method validation, and the methods were approved official first action. During 1989 through 1992, the split-sample collaborative study format was used to monitor the performance of these methods as a part of an ongoing quality assurance program for a group of laboratories. Seven blind duplicate samples of raw milk were sent from a central laboratory once every 2 months to each participating laboratory (11 to 17 laboratories). Data were analyzed by using the same statistical procedures used in the 1988 study. Over time, both the within- and between-laboratory performances of both methods were as good as or, in most cases, better than the results from 1988. The data demonstrate that the statistical protocol for collaborative studies can be used effectively as the basis for a multilaboratory quality assurance program and that the method performance achieved in a collaborative study can be maintained and even improved with time.

Development of the Quality Management System for Borehole Investigations: Part 1—Quality Assurance and Quality Control Methodology for Hydraulic Packer Testing

2010 ◽  
Author(s):  
Shinji Takeuchi ◽  
Takanori Kunimaru ◽  
Kunio Ota ◽  
Bernd Frieg
Keyword(s):  
Quality Control ◽  
Quality Assurance ◽  
Data Analysis ◽  
Quality Management System ◽  
Test Method ◽  
Hydraulic Test ◽  
Pressure Transducers ◽  
Field Investigations ◽  
Packer Testing ◽  
Pressure Changes

A quality assurance and quality control (QA/QC) system for the hydraulic packer tests has been established based on the surface-based investigations at JAEA’s underground research laboratories in Mizunami and Horonobe. The established QA/QC system covers field investigations (data acquisition) and data analysis. For the field investigations, the adopted procedure is selection of a test section based on a detail fluid logging and checking with tally list, followed by inspection of test tools such as pressure transducers and shut-in valves, etc., test method selection using a “sequential hydraulic test” for deciding appropriate method, and finally data quality confirmation by pressure changes and derivatives on a log-log plots during testing. Test event logs should also be described during testing for traceability. For the test data analysis, a quick analysis for rough estimation of hydraulic parameters, and a detailed analysis using type curve and/or numerical analyses are conducted stepwise. The established QA/QC system has been applied to the recent borehole investigations and its efficiency has been confirmed.

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